Support of materials above the user's lap provides freedom of movement for the lower body compared to lap boards which must be placed upon the lap. Support of the user's arms, as well as materials and the hands, gives added relief to shoulder muscular tension. Elevation also beings materials to an appropriate visual range thus decreasing downward flexion of the neck. U.S. Pat. No. 3,147,949 discloses a lapboard that is somewhat elevated and inclined rather greatly while being supported on the lap. U.S. Pat. No. 3,730,077 discloses a collapsible lapboard that elevates a clipboard above the user's lap, taking on some of the character of a desk surface. Another lap desk supported directly on the lap is disclosed by Jennings, in U.S. Pat. No. 4,052,944.
Supports can also hold the work surface above the user's body and allow free movement of leg positions as in the case of bedtrays. As disclosed in detail in parent application Ser. No. 07/264,838, supports are employed which extend to the seat surface upon which the user is seated, or the portable desk may be placed on a table where it achieves a total height suitable for a standing work site or a speakers stand. A seated user of this desk is allowed some freedom of movement since the desk is not supported directly on the lap.
Alternative sites on which to support a desk unit above the lap of a seated user are the arms of a chair rather than the seat surface of a chair. Such sites of support to the arms of a chair is shown in U.S. Pat. No. 4,467,991, which has extensions of the desk frame aligned with the arms.